Chapter 4
Sleep Deprivation
4001. CHALLENGES OF SLEEP DEPRIVATION
People accumulate a “sleep debt” (cumulative loss of sleep over
time) when they perform under limited sleep conditions. The only
corrective measure for satisfying this sleep debt is sleep itself. Military operations, by their demanding nature, create situations where
obtaining needed sleep will be difficult or impossible for more than
short periods.
Continuous operations are military operations with many pulses
of action every day and night, continuing for several days to weeks,
which require careful planning and resource allocation to give
everyone a minimum of 4 hours sleep in 24. (FM 22-51)
Sustained operations are continuous operations or combat with
opportunity for less than 4 hours sleep per 24 hours for significant
personnel, which may be brief or fragmented. (FM 22-51)
Accordingly, service members may have opportunities for only limited or fragmented sleep over an extended period. As a result of
these periods of sleep loss, several combat tasks are likely to show
decreased performance. These tasks include the following:
l
Orientation with friendly and enemy forces (knowledge of the
squad’s location and maintaining camouflage, cover, and
concealment).
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l
Coordination and information processing (coordinating firing
with other vehicles and dismounted elements, reporting vehicle readiness, and communicating with the headquarters).
l
Combat activity (firing from bounding vehicle, checking the
condition of weapons, observing the terrain for enemy presence).
l
Force preservation and regrouping (covering disengaging
squads, marking the routes between locations, and conducting
reconnaissance).
l
Command and control activity (directing location repositioning,
directing mounted defense, assigning fire zones and targets).
MCRP 6-11C
Continuous operations will potentially be more commonplace on
the battlefield. In offensive operations, darkness is the time to
retain or gain the initiative; while in defensive operations, obstacles can be employed with greater security during darkness.
Forces can disengage undetected and threats to close air support
lessen. The physical environment changes at night. As the air
cools below ground temperature, inversions reduce visibility and
hamper radar and radio signals. Conditions are optimal for using
chemical weapons. Visual changes also occur. Without the aid of
white light, there is no color perception. There is also a decrease
in visual clarity, field of view, and depth perception. Targets take
longer to engage. Preparation time increases two-fold to six-fold.
Simple actions, such as the departure and return of patrols,
become more complex and dangerous. Nighttime planning and
coordination require greater attention. Navigation, adjusting fire,
and munitions and/or target matching are more difficult. Precision is essential, but accuracy has a price. Service members tend
to maintain accuracy at the sacrifice of speed. The adverse conditions associated with or generated by continuous ground combat
at night will degrade the fighting performance of Service members, teams, and units. The almost complete mechanization of
Combat Stress _____________________________________________ 59
land combat forces and technological advances that permit effective movement at night, during poor weather conditions, and
under conditions of limited visibility have largely overcome the
reasons for “traditional” pauses in battle, such as darkness, resupply, and regrouping. New technologies have significantly
increased the range, reduced the time, and changed the conditions
over which battles are fought. For example, day/night-capable
vehicles can operate for extended periods without re-supply, but
they are limited by a crew’s need to sleep. A Service member is
not a machine and is, therefore, the weak link in the chain. The
equipment can operate longer than the Service member who operates it, as the Service member must have sleep.
Commanders and leaders must ensure that all Service members
obtain enough rest to counteract the effects of rapidly shifting
from daytime to nighttime duty hours, or to extended work schedules. Implementing countermeasures that are designed to help
Service members adapt to continuous operations conditions can
satisfy this requirement. Neither leaders nor their subordinates
can perform without rest or sleep. The Service member, the unit,
and the leader are all affected by continuous operations. Generally at night, the cognitive and physiological resources of Service
members are not at their peak, especially after a rapid shift from
daytime to nighttime duty hours. Fatigue, fear, feelings of isolation, and loss of confidence may increase.
Non-stop, unrelieved combat operations (sustained operations)
with little or no sleep degrade performance and erode mental abilities more rapidly than physical strength and endurance. Information gained from the Army Unit Resiliency Analysis Model
shows that even healthy young Service members who eat and
drink properly experience a 25 percent loss in mental performance for each successive 24-hour period without sleep. The
mental parameters include decisionmaking, reasoning, memory
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MCRP 6-11C
tasks, and computational tasks. The loss may be greater for Service members who are older, less physically fit, or who do not eat
and drink properly.
The effects of sustained operations are sometimes hidden and difficult to detect. Units are obviously impaired when Service members are killed or wounded in action or become noncombatant
losses. They are further impaired when their troops are too tired
to perform their tasks. Unlike individual performance, unit performance does not deteriorate gradually. Units fail catastrophically, with little warning.
A priority for fighting units is to assure that commanders and
leaders are rested and able to think clearly. While this is obvious,
it is a most difficult lesson for leaders to learn. During combat,
commanders must focus on the human factor. They must assess
and strengthen their units as they plan and fight battles. They
must accurately decipher which units must lead, which must be
replaced, where the effort must be reinforced, and where tenacity
or audacity and subsequent success can be exploited. When leaders begin to fail, control and direction become ineffective, and the
organization disintegrates. No fighting unit can endure when its
primary objectives are no longer coordinated. Leaders must also
prepare and precondition Service members to survive. It is particularly important that leaders conscientiously plan and implement
effective sleep plans, because activities that are most dependent
on reasoning, thinking, problem solving, and decision-making are
those that suffer most when sleep and rest are neglected.
Some leaders wrongly believe that their round-the-clock presence
during an operation is mandatory; they are unwilling to recognize
that they, too, are subject to the effects of sleep deprivation. If the
unit has been regularly trained according to the mission command
philosophy, two benefits accrue. Not only will a leader be confident that in his absence his subordinates will adhere to his intent,
Combat Stress _____________________________________________ 61
but the trust he shows in his subordinates will continue to maintain unit morale and help ease some of the stress of the situation.
In future operations, the battlefield will become increasingly
lethal. The threat of nuclear, biological, and chemical weapons
will maximize confusion, uncertainty, and stress, which adversely
impact our ability to move, shoot, communicate, and sustain.
Sleep loss in this type of environment increases an already stressful situation.
4002. EFFECTS OF SUSTAINED
OPERATIONS ON PERFORMANCE
A basic rule for continuous operations is planning ahead to avoid
sustained operations, and provide members 5 to 6 hours sleep in
24. However, missions or enemy actions sometimes require
exceptional exertion for several days with only unpredictable,
fragmented sleep—as required in sustained operations. Sustained
combat leads to exhaustion and reduction in effective task performance. Even during the first night of combat, normal sleeping
habits and routines are abnormal. The Service member feels the
effects of fatigue and the pressure of stress from noise, disrupted
sleep time, and threat to life. While essential for endurance, sheer
determination cannot offset the mounting effects of adverse conditions. Cognitive degradation involving poor decisionmaking
begins during and after the first 24 hours of sleep deprivation.
Individual and unit military effectiveness is dependent upon initiative, motivation, physical strength, endurance, and the ability
to think clearly, accurately, and quickly. The longer a Service
member goes without sleep, the more his thinking slows and
becomes confused. Lapses in attention occur, and speed is sacrificed to maintain accuracy. Continuous work declines more rapidly than intermittent work.
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MCRP 6-11C
Tasks such as requesting fire, integrating range cards, establishing positions, and coordinating squad tactics become more difficult than well-practiced, routine physical tasks, such as loading
magazines and marching. Without sleep, Service members can
perform the simpler and/or clearer tasks—lifting, digging, and
marching—longer than the more complicated or ambiguous tasks
such as a fine hand-eye coordination sequence; i.e., tracking a target through a scope.
Sleep loss affects memory, reasoning, mental assessments, decision-making, problem-solving, subsequent actions, and overall
effectiveness. While comprehension is accurate, reading speed
slows and recall fails. For example, Service members may understand orders when reading them in documents, yet they are forgotten later when required. Individuals will forget or omit
assigned tasks more often than they will make errors in carrying
them out.
Leaders can expect declining moods, motivation, initiative, planning ability, and preventive maintenance. High motivation will
only increase risk, due to impaired performance. Leaders must
recognize erratic or unreliable task performance in subordinates,
as well as in themselves. Alertness and performance decline gradually with partial sleep deprivation; that is, when sleep is limited
to 4 to 5 hours per night. After 5 to 7 days of partial sleep deprivation, alertness and performance decline to the same low levels
as those following 2 days of total sleep deprivation. After 48 to
72 hours without sleep, personnel become militarily ineffective.
Adverse Conditions
Continuous combat forces Service members to perform under
adverse conditions that cause degradation in performance. Examples of adverse conditions follow.
Combat Stress _____________________________________________ 63
Low Light Level
The amount of light available for seeing landmarks, targets, and
maps is greatly reduced at twilight and night.
Limited Visibility
Smoke, fog, rain, snow, ice, and glare degrade a Service member’s ability to see his environment and objects within it, as
opposed to situations free of such conditions.
Disrupted Sleep Routines
People are accustomed to being awake or asleep during certain
hours of the day or night. Disruption of the normal sleeping
schedule causes degraded performance.
Physical Fatigue
Working the muscles faster than they can be supplied with oxygen and fuel rapidly creates “oxygen debt,” eventually making
these muscles unable to function until the deficits are made up
during brief rests.
Sleep Loss
The muscles can continue to function adequately without sleep,
but the brain cannot. Increasing sleep debt leads to subtle, but
potentially critical, performance failures.
Sleep Loss Indicators
Indications of degraded performance symptoms become more
prevalent as sleep debt accumulates. Performance is affected by
the hours of wakefulness, tolerance to sleep loss, and the types of
mental or physical work. Both mental and physical changes
occur, with symptoms varying among individuals. Leaders must
observe Service members for the following indications of sleep
loss and degraded performance:
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l
Physical changes in appearance, including vacant stares,
bloodshot eyes, pale skin, and poor personal hygiene. Other
physical signs of sleep loss include the body swaying when
standing, sudden dropping of the chin when sitting, occasional
loss of hand-grip strength, walking into obstacles or ditches,
low body temperature, slowed heart rate, and slurred speech.
l
Mood changes, decreased willingness to work, and diminished performance go hand-in-hand. Service members may
experience decreasing levels of energy, alertness, interest in
their surroundings, and cheerfulness with a concurrent
increase in irritability, negativity, and sleepiness. Some
become depressed and apathetic. Others, for a time, can
become energized by sleep loss, talk more, and may be more
assertive without necessarily maintaining good judgment.
Sleepiness and mood changes are not signs of weakness. After
long periods of sleep loss, Service members go from being
irritable and negative to dull and weary.
l
Service members may feel more effort is needed to perform a
physical task in the morning than in the afternoon. Exaggerated
feelings of physical exertion may lead to work stoppage, especially between 0400 and 0700. During that time, the tendency
to fall asleep is considerably more noticeable than other times.
l
Both bickering and irritability increase with sleep loss. When
Service members argue, it shows that they are still talking to
each other and exchanging orders and messages. When arguments cease, especially after a period of increased bickering,
Service members may be in a state of mental exhaustion.
l
Comprehension and perception slow considerably. Individuals
require extended time to understand oral, written or coded
information; to find a location on a map and/or chart coordinates; to interpret changes in enemy fire patterns; and to make
sense of things seen or heard, especially patterns. They may
MCRP 6-11C
Combat Stress _____________________________________________ 65
have difficulty with spot status or damage reports, and may be
unable to assess simple tactical situations.
Loss of Concentration
Sleep deprivation causes the attention span to shorten. There is a
loss of concentration on the job as dream-like thoughts cause
lapses in attention. Leaders should watch for the following:
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Decreased vigilance. Personnel are less alert and fail to detect
the appearance of targets, especially in monotonous environments. They may doze off at the wheel of moving vehicles.
l
Distorted attention. Service members may imagine seeing
things that are not there, e.g., “moving” bushes when in reality
there is no such movement. The sleep-deprived brain can also
misperceive bushes, rocks, people, vehicles or anything else
and see them as something different, in very precise detail.
Often the tired brain “sees” what it wishes were there (food, a
bed); at other times, these illusions may be animals or other
more bizarre things. But when the mind is alert for an enemy,
the brain may generate a very convincing, detailed image of
the enemy. Sometimes, but not usually, sounds or other sensations may accompany these illusions. They usually last only
seconds, but can persist for minutes if not challenged, and
rarely have even been “seen” by equally sleep-deprived comrades when told of them. It is essential for sleep-deprived unit
members to check out any questionable things they see with
their comrades, and to faithfully follow reporting and challenge procedures.
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Inability to concentrate; easily confused. Service members
cannot keep their minds on what they are doing. They cannot
follow multiple directions nor perform numerical calculations.
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l
Failure to complete routine tasks. Sleep loss interferes with
completing routine individual tasks, such as drying the feet,
changing socks or filling canteens when water is available.
Tasks such as performing weapons checks may be skipped.
MCRP 6-11C
When a Service member cannot recall what he just saw, read,
heard or was told by another individual, he is exhibiting a common sign of sleep loss. His memory loss is limited to recent
events. For example, a sleep-deprived Service member may forget recent target data elements or recall them incorrectly and have
difficulty learning new information.
4003. ACHIEVING SLEEP IN COMBAT
Sleep deprivation produces stress and, therefore, sleep management is important. Sleep management is a combat multiplier.
Planned sleep routines are important for keeping the unit, the
individual Service members, and the leader himself functioning
as required while reducing sleepiness during continuous combat.
Since leaders are responsible for planning sleep routines, they
need a basic understanding of the physiological and behavioral
aspects of sleep and their impact on performance. The following
paragraphs provide this information.
Rhythmic Variations
There are rhythmic variations in individual performance based on
a predictable physiological and behavioral cycle that comprises
about 24 hours. The 24-hour, day-night/work-rest cycle is called
the circadian rhythm. Because traveling across a half-dozen time
zones disrupts the usual relationship in the day-night/work-rest
cycle, for a few days Service members are not sleepiest at their
usual sleep period of 2400 to 0600, new-locale time. Allowing
Combat Stress _____________________________________________ 67
sleep about 1200 to 1800, new-locale time, will only delay their
adaptation to their new locale. Leaders must instruct troops to go
to bed between 2400 and 0600 new-local time to establish a new
circadian rhythm.
Another example of circadian rhythm is body temperature.
Although one’s “normal” temperature is 98.6 degrees, this is
really an average or midpoint of a daily swing from 96.8 to 100.8
degrees. For someone accustomed to working days and sleeping
nights, body temperature would fluctuate approximately as indicated. There is a well-established link between body temperature
and sleepiness and/or performance slumps. Performance parallels
body temperature. The higher the body temperature, the better the
performance. As body temperature decreases, mood and motivation decline with a concurrent increase in sleepiness and fatigue.
Impact upon performance is most pronounced during the circadian lull, which is roughly 0200 to 0600 hours. During this time,
performance declines about 10 to 15 percent. In sleep-deprived
Service members, this decline may reach 35 to 40 percent. If the
day-night/work-rest cycle is disrupted, performance suffers
because the Service member is sleepy during the new work
period and awake during the new sleep period. The body needs
several days to adjust to the new schedule. Critical hours for sleep
are between 0200 and 0600 when anchor sleep (the most beneficial sleep) is taken. The body is at its lowest temperature during
this period. This is the best time for sleeping, but not for napping.
To prevent sleep inertia, naps should always be taken at times
other than the lowest point in body temperature.
Leaders need to calculate the difference in time zones and make
the necessary schedule changes. Leaders will need day-and nightfighting teams. Members acclimated to working days and sleeping nights should be scheduled to work nights and sleep days.
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MCRP 6-11C
Their performance slump/optimal time to sleep would be 2400 to
0600, new-locale time. Deployment, pre-combat, and combat are
not usual circumstances. If certain Service members must have an
offset circadian timing from the rest of the unit, a special effort
must be made to establish their sleeping time. Obviously, troops
must sleep whenever possible. If a planned sleep schedule cannot
be followed, however, performance is enhanced if sleep coincides
with the low point in body temperature.
Adjusting to new circadian rhythms is a slow process, taking 3 to
6 days to come “in phase” with a new schedule. Leaders should
devise a sleep schedule that provides for sleep at the same time of
day or night every 24 hours. Sleep schedules that provide for
sleep at different times of day or night are less valuable and are
detrimental to quality sleep and optimal performance.
Sleep Shifts
Staggered work schedules can be set up for two shifts working 4
hours on/4 hours off, 6 hours on/6 hours off, and 12 hours on/12
hours off. See Table 4-1. Each shift follows the same schedule
daily. It is better to maintain regular shift schedules than schedules that continually change.
Sleep/Rest Guidelines
Leaders should use the following sleep and/or rest guidelines in
this section to enhance individual and the unit performance in
continuous operations.
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Know personal tolerance for sleep loss and those under your
command; major individual differences are not easily
changed. Individuals who are unable to sleep during predeployment and deployment stages should be encouraged to
practice relaxation exercises (see paragraph 2005).
Combat Stress _____________________________________________ 69
Table 4-1. Sleep Shifts.
4 HOURS ON/4 HOURS OFF
Shift
24000400
04000800
08001200
12001600
16002000
20002400
1
SLEEP
DUTY
SLEEP
DUTY
SLEEP
DUTY
2
DUTY
SLEEP
DUTY
SLEEP
DUTY
SLEEP
6 HOURS ON/6 HOURS OFF
Shift
24000600
06001200
12001800
18002400
1
SLEEP
DUTY
SLEEP
DUTY
2
DUTY
SLEEP
DUTY
SLEEP
12 HOURS ON/
12 HOURS OFF
Shift
24001200
12002400
1
SLEEP
DUTY
2
DUTY
SLEEP
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Ensure that Service members fully use their breaks and other
opportunities for rest. Encourage them to waste no time in getting to sleep. Undisturbed, prolonged sleep is the most desirable use of rest opportunities. When there has been sleep loss
but little physical exertion (e.g., manning communications,
operating a radio), mild physical exercise such as walking
around when conditions permit, can help maintain alertness.
l
Encourage Service members to sleep, not just rest, by creating
the most conducive environment possible for sleep: quiet,
without interruptions (or earplugs); dimness or darkness (or
with eye cover); not overly warm or cold.
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l
Do not allow personnel to sleep in unsafe conditions. Enforce
strict rules designating sleep areas and requiring perimeter
guards. Require day and night guides for all vehicles to prevent Service members from being accidentally run over.
l
Ensure that Service members follow sleep schedules or routines. The field commander who does not enforce a sleep
schedule or routine leads his troops into an environment that
increases the opportunity for hazardous conditions to be
encountered while in continuous combat. Taking naps is not a
sign of low fighting spirit or weakness; it is a sign of foresight.
MCRP 6-11C
Measuring Sleep Loss
Sleep loss can be measured by:
l
Keeping a sleep and/or activity log. From pre-deployment to
post-deployment, log sleep and nap periods. Service members
need 4 to 5 hours per 24-hour period; 6 or 7 hours is optimum.
If they receive less, the first chance for a long rest period must
be used for sleep.
l
Observing performance and asking questions. Look for the
indications of sleep loss—such as increase in error occurrence, irritability, difficulty understanding information, and
attention lapses—with concurrent decreases in initiative,
short-term memory, and attention to personal hygiene. Confirm sleep loss by asking the obvious question: “When did you
sleep last and how long did you sleep?”
Sleep Loss Alternatives
Ways to overcome performance degradation include:
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Upon signs of diminished performance, find time for members
to nap, change routines or rotate jobs (if cross-trained).
Combat Stress _____________________________________________ 71
l
Have the Service members most affected by sleep loss execute
a self-paced task.
l
Have Service members execute a task as a team, using the
buddy system.
l
Do not allow Service members to be awakened for meals
while in flight to a new location, especially if the time zone of
the destination is several hours different than that of point of
departure.
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Insist that Service members empty their bladder before going
to bed. Awakening to urinate interrupts sleep, and getting in
and out of bed may disturb others and interrupt their sleep.
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Allocate sleep by priority. Leaders, on whose decisions mission success and unit survival depend, must get the highest
priority and largest allocation of sleep. Second priority is
given to Service members that have guard duty and to those
whose jobs require them to perform calculations, make judgments, sustain attention, evaluate information, and perform
tasks that require a degree of precision and alertness.
4004. SLEEP/REST PLANNING
Sleep/rest planning applies to the pre-deployment, deployment,
pre-combat, combat, and post-combat stages of battle.
Pre-Deployment Stage
Using mission-scenario operation guidelines, determine periods
available for sleep and the total number of sleep hours possible.
Because continuous operations requirements may change, alternate sleep routines should be planned. Become familiar with the
area where the combat unit will sleep; For example, some may
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MCRP 6-11C
have to sleep in mission-oriented protective posture (MOPP) IV.
If sleeping in MOPP IV is anticipated in combat, practice it during the pre-deployment stage. Prior experience reduces stress, so
practice anticipated sleep routines before continuous operations.
Deployment Stage
Since sleep will be reduced during deployment, follow preplanned sleep routines. The prudent commander will choose a 4hour on/4-hour off, 6-hour on/6-hour off, or 12-hour on/12-hour
off shifts from the start. Take into account that Service members
on night duty will need to sleep during the daytime. Provide
night-shift personnel with separate sleeping quarters to avoid disruption of their sleep period.
Pre-Combat Stage
In general, people are most effective during the afternoon and are
least effective just before dawn. Without prior adjustment to the
new time zone, which naturally occurs in 3 to 5 days, leaders can
expect degraded daytime performance. The reason is that 0200 to
0600 hours home-base time is the low point in performance efficiency and should be considered when planning workloads.
Combat Stage
Every effort should be made to avoid situations where all personnel are physically and mentally exhausted simultaneously. Make
the most of any lull during the combat phase by sleeping briefly.
Complete recovery from sleep loss may not be possible during
intense combat, but limited sleep is helpful. Uninterrupted short
sleeps of 15 minutes or longer are beneficial to partially recovering alertness. Sleep during the combat stage may be risky, how-
Combat Stress _____________________________________________ 73
ever, because a Service member may wake up feeling groggy,
confused, sluggish, and uncoordinated. It may take his brain from
several seconds to 15 minutes to “warm up.” Individuals differ in
how quickly they take to wake up, but it tends to be worse when
the body expected to go into deep sleep, and to get worse with
increasing sleep loss. Activities that increase circulation of warm
blood to the brain, like moderate exercise or drinking a hot beverage, may shorten the start-up time.
Post-Combat Stage
It is important to make up sleep debt, but experts disagree about
the amount of recovery time needed. Some say the hours of sleep
needed for recovery after sleep deprivation are less than the
amount lost. It is well known and documented that lost sleep is
not made up hour-for-hour. Most experts agree that immediately
following continuous combat, Service members should be
allowed to sleep up to 10 hours. Longer sleep periods are not
desirable because they cause “sleep drunkenness” and delay in
getting back to a normal schedule. After the first sleep period of
up to 10 hours, Service members should return to the regular
sleep routine. Sleep inertia lasting longer than 5 to 15 minutes
and increased sleepiness may occur for as long as a week following sustained combat. Some experts recommend that 4 of the first
8 hours of recovery sleep should be at the 0200 to 0600 sleep
time, and they suggest the following guidelines for complete
recovery from the effects of sleep loss:
l
12 hours for sleep and rest after 36 to 48 hours of complete
sleep loss with light to moderate work load (fatigue may linger for 3 days).
l
24 hours for sleep and rest after 36 to 48 hours of sleep loss
with high workload (12 to 16 hours per day).
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2 to 3 days time off after 72 hours or more of acute sleep loss.
l
As much as 5 days for sleep and rest following 96 hours or
more of complete sleep loss.
MCRP 6-11C
Most experts agree that 10 hours of sleep is the maximum
needed, with the additional 2 hours used for rest. It is doubtful
that a Service member could continue past 72 hours of wakefulness. Should this occur, a couple of nights with 10 hours of sleep
are more beneficial than an excess of 10 hours during one sleep
period. If Service members have not slept for 36 to 48 hours or
more, they should avoid sleep of less than 2 hours, especially
between 0400 and 0600. A too-short sleep period at the wrong
time may cause a long period of sleep inertia. After 96 hours of
total wakefulness, 4 hours of sleep may provide substantial
recovery for the simpler, less-vulnerable tasks. Recovery continues with additional days of 4 hours of sleep per 24 hours. Complex leadership tasks may require longer recovery sleep, but sleep
until fully satisfied is not necessary.
Sleep loss alone does not cause permanent health problems, nor
does it cause mentally healthy people to become mentally ill.
Reduced sleep (from 8 to 4 hours) does not cause physical harm.
Hallucinations may occur, but they disappear after recovery
sleep. Clinical laboratory tests show that total sleep loss of over a
week does not pose serious health problems. It is doubtful that
Service members could stay awake for such an extended period,
and it is not suggested that Service members try to endure long
periods without rest. However, the effects of sleep loss, such as
inattentiveness and poor judgment, may be harmful (such as falling asleep at the wheel of a vehicle).
Sleep cannot be stored in our bodies for emergency use. Sleep of
more than 7 to 8 hours before deployment does not “store up”
Combat Stress _____________________________________________ 75
excess sleep, but sleep taken immediately before a deployment
can prolong activity. Therefore, it is important to begin continuous operations in a rested state. During daytime or early morning
naps, many Service members experience vivid dreams as they fall
asleep and often wake up frightened. Leaders should inform their
troops that this occurrence is both common and normal during
daytime sleep. If a single, unbroken period of 4 to 5 hours is not
available for sleep, “power naps” of 15 to 30 minutes, although
less recuperative, can be taken. Leaders must capitalize on every
opportunity for a “power nap.” Merely resting by stretching out
does not take the place of sleep. Only sleep can satisfy the need
for sleep.